The complex interrelationships and overlapping needs of the research projects that comprise this Program Project require a Core program under which activities affecting all projects and all participating investigators can be performed. The Core activities will include 1) all administrative functions including management of budgets, purchasing, personnel matters, inventory control, travel, communication, word processing, manuscript preparation; 2) biostatistical consulting, data management, and data processing; 3) major emphasis on communications among participating investigators, and interactions with other investigators within the Institution and beyond, who are working on basic and clinical aspects of periodontal diseases and other related areas; 4) consultants and visiting scientist program; 5) program performance evaluation; and 6) coordination of training activities. The Core program will centralize all administrative procedures and other nonresearch tasks, so as to free each individual from other administrative responsibilities and thus afford the maximum amount of time for research.